In recent days the science sections of the media have been full of the successful entering of orbit around Jupiter by the NASA probe Juno after its five-year, 2.8 billion kilometre journey from the Earth. Many of the reports also talk about the so-called Galilean moons, Jupiter’s four largest moons (there are currently 67 known moons of Jupiter), and Galileo’s discovery of them with the recently invented telescope in early 1610.

Montage of Jupiter’s four Galilean moons, in a composite image depicting part of Jupiter and their relative sizes (positions are illustrative, not actual). From top to bottom: Io, Europa, Ganymede, Callisto. Source: Wikimedia Commons

Juno was even carrying Lego models of the god Jupiter, the goddess Juno and Galileo holding a telescope.